Method for Reducing Marine Pollution Using Polyhydroxyalkanoate Microbeads

Abstract

Herein we describe a method for the reduction of pollution in aquatic systems by incorporating polyhydroxyalkanoate microbeads into personal care formulations such as exfoliants, cosmetics, and toothpaste. Suitable polyhydroxyalkanoate microbeads are biodegradable, have an average size of less than 400 microns, and sink rapidly in aquatic environments.

We claim: 
     
         1 . A method for reducing microplastic pollution in waste streams comprising:
 applying a personal care formulation to a human body; and   rinsing said formulation off of the human body with water,   wherein the rinsewater from said rinsing step ultimately drains into an aquatic environment selected from the group consisting of a wastewater treatment facility, a septic system, a stormwater system, a sewer system, a surface waterbody, and a groundwater aquatic environment; and   wherein said formulation comprises polyhydroxyalkanoate microbeads having an average size of less than 400 microns.   
     
     
         2 . The method of  claim 1 , wherein at least 95% of the volume of said polyhydroxyalkanoate microbeads sinks below the water surface level at the one hour conclusion of a standard settling test conducted according to the Standard Methods for the Examination of Water and Wastewater, Section 2540F. 
     
     
         3 . The method of  claim 1 , wherein at least 90 percent of the monomer units of said polyhydroxyalkanoate microbeads are hydroxybutyrate units. 
     
     
         4 . The method of  claim 1 , wherein at least 25% of said polyhydroxyalkanoate microbeads are sequestered into sediment at the bottom of said aquatic environment within 10 days of said polyhydroxyalkanoate microbeads being drained into said aquatic environment. 
     
     
         5 . The method of  claim 1 , wherein said polyhydroxyalkanoate microbeads have an average circularity of greater than 0.95. 
     
     
         6 . The method of  claim 1 , wherein said polyhydroxyalkanoate microbeads have an average circularity of greater than 0.35 and less than 0.75. 
     
     
         7 . The method of  claim 1 , wherein said polyhydroxyalkanoate microbeads have an average hardness of between 0.5 and 3.5 on the Mohs scale. 
     
     
         8 . The method of  claim 2 , wherein at least 25% of the volume of said polyhydroxyalkanoate microbeads settle to the bottom at the one hour conclusion of a standard settling test conducted according to the Standard Methods for the Examination of Water and Wastewater, Section 2540F. 
     
     
         9 . The method of  claim 2 , wherein at least 95% of the volume of said polyhydroxyalkanoate microbeads settles to the bottom at the one hour conclusion of a standard settling test conducted according to the Standard Methods for the Examination of Water and Wastewater, Section 2540F. 
     
     
         10 . The method of  claim 1 , wherein said polyhydroxyalkanoate microbeads additionally comprise a coloring agent. 
     
     
         11 . A method for reducing microplastic pollution in waste streams comprising:
 formulating a personal care product useful for cleaning or protecting human body surfaces, and   directing users to apply said product to human body surfaces to clean said body surfaces;   wherein said product is rinsed by said users and ultimately drains into an aquatic environment selected from the group consisting of a wastewater treatment facility, a septic system, a stormwater system, a sewer system, a surface waterbody, and a groundwater aquatic environment; and   wherein said product comprises polyhydroxyalkanoate microbeads having an average size of less than 400 microns.   
     
     
         12 . The method of  claim 11 , wherein at least 95% of said polyhydroxyalkanoate microbeads sink below the water surface level at the one hour conclusion of a standard settling test conducted according to the Standard Methods for the Examination of Water and Wastewater, Section 2540F. 
     
     
         13 . The method of  claim 11 , wherein at least 90 percent of the monomer units of said polyhydroxyalkanoate microbeads are hydroxybutyrate units. 
     
     
         14 . The method of  claim 11 , wherein at least 25% of said polyhydroxyalkanoate microbeads are sequestered into sediment at the bottom of said aquatic environment within 10 days of said polyhydroxyalkanoate microbeads being drained into said aquatic environment. 
     
     
         15 . The method of  claim 11 , wherein said polyhydroxyalkanoate microbeads have an average hardness of between 0.5 and 3.5 on the Mohs scale. 
     
     
         16 . The method of  claim 12 , wherein at least 95% of the volume of said polyhydroxyalkanoate microbeads settles to the bottom at the one hour conclusion of a standard settling test conducted according to the Standard Methods for the Examination of Water and Wastewater, Section 2540F. 
     
     
         17 . The method of  claim 11 , wherein said polyhydroxyalkanoate microbeads have an average circularity of greater than 0.35 and less than 0.75. 
     
     
         18 . The method of  claim 11 , wherein said personal care product is toothpaste. 
     
     
         19 . The method of  claim 11 , wherein said personal care product is an exfoliating product. 
     
     
         20 . The method of  claim 11 , wherein said personal care product is a soap bar.